1. Field of the Invention
The present invention relates to a production technique of a non-fitting type capsule, and more particularly to a technique for producing a non-fitting type capsule containing an oily substance.
2. Related Art Statement
Soft capsules containing a oily substance have widely been used in the fields of medicine, food, etc. These soft capsules comprise an oily substance such as medicine, i.e., oil-soluble vitamins including Vitamin A, D, E, etc., cod-liver oil, linoleic acid, etc.; healthy food: or those in which an oil-soluble medicine is dissolved in a vegetable oil, etc; being contained in an outer shell made of gelatin, etc.
In general, for preparing the above soft capsules, a rotary type automatic encapsulation machine having a structure as shown in FIG. 2 has been used.
An oily substance 11 to be filled in capsules is supplied from a tank which is not shown through a pipe into a cylinder pump 12. A gelatin sheet 13 which is to constitute an outer shell is molded into a sheet from an aqueous gelatin solution which was heated to be dissolved in a previous step which is not shown, and after transferred to a die roll 14 in a heated state, it encapsulates therein the oily substance 11 supplied by the cylinder pump 12 and is formed to be a soft capsule 15 by heat pressing. The oily substance 11 is supplied to the die roll 14 generally in a heated state so as not to lower a temperature of the heat pressing.
In the aforesaid rotary type automatic encapsulation machine, it is difficult to broaden the width of the flow passage of the oily substance in view of its structure and the oily substance is supplied from the tank to the cylinder pump by gravity-drop.
Thus, if an oily substance having high viscosity is used, a large load must be applied for suction of the cylinder pump even when the viscosity is reduced to some extent by heating, whereby working failure tends to be caused when same production speed of capsules as low viscosity oil is employed. Therefore, production speed of capsules must be lowered.
To cope with this, it may be considered to supply an oily substance by using an additional pump in combination. It, however, is difficult since suction of the oily substance by a cylinder pump is intermittent.
Also, it may be considered to lower viscosity by adding a hydrophobic solvent or other low viscosity oily substance to a high viscosity oily substance. But, as a hydrophobic solvent, there is no suitable material which can be utilized together with medicine, food, etc. On the other hand, as shown in Table 1 below, an oily substance has generally much higher viscosity than a hydrophobic solvent, so that a viscosity lowering effect is small even when another oily substance with lower viscosity is added. As can be seen from these facts, it is the present situation that soft capsules containing a high viscosity oily substance cannot be produced with high efficiency.
TABLE 1 ______________________________________ Viscosities of various kinds of oily substances Oily Viscosity (cps) substance 25.degree. C. 37.7.degree. C. ______________________________________ Vitamin E 320 Castor oil 651 263-290 Olive oil 75 43 Rapeseed oil 82 51 Soybean oil 28.49 Liver oil 32.79 (Codfish) ______________________________________ (Vitamin E is a measured value by the inventor, others are values shown i "Yushi Kagaku Binran" ("Oil and Fats Chemistry Handbook", in Japanese)